Lepidolite enamel and method of producing same



Patented Nov; 5, 1929 UNITED STATES TRENZEN, OI HONNEF-ON-THE-BHINE, GERMANY,

PATENT OFFICE ASSIGNOR OF TWO-THIBDS TO CARL SCHWARTZ AND G. GUTHRIE HUNTER, BOTH 01 NEW YORK, N. Y.

Lnnnomrr: ENAMEL AND mn'rnon or rnonocme same No Drawing. Application filed July 9, 1926, Serial No. 121,502, and in. Germany July 10, 1925.

I have discovered that the known material lepidolite is particularly suited for enamelling of goods composed of iron and the use of this material has the particular advantage that an undercoat enameling is not necessary. \Vhich, of the mineral components of lepidolite, are responsible for this phenomen, namely that it is not necessary to burn in an undercoat enamel, has not been possible to ascertain definitely, although it is surmised that the lithium is the cause thereof.

' A lepidolite of the following composition:

Per cent Silica 50,38 Alumina 25,96 Iron oxide 0,14 Lime 0,08

Magnesium oxide 0,03 Lithium oxide 4,94 Potash, potassium oxide 7,21 Sodium oxide 5,21 Fluorine Q. s. 7,20

is pulverized to the greatest fineness and is,

v without any other binders, floated with water upon the objects to be enameled and is burned dered lepidolite directly in contact with the metal, and thereafter subjecting the article to a baking temperature.

2. The method of enameling a metal article which consists in applying a coating of powdered lepidolite, carried by a fluent vehicle, directly in contact with the metal, and thereafter subjecting the article to a baking temperature.

3. The method of enameling a metal article which consists in floating directly onto the metal powdered lepidolite, mixed in water, and thereafter subjecting the article to a baking temperature.

4:. As an article of manufacture, a piece of metallic stock having baked thereon a coating including lepidolite, said coating having a co-efiicient of expansion difii'ering from that of lepidolite and being in direct contact with the stock.

In testimony whereof I affix my signature.

DR. CARL TRENZEN.

much as lithiumoxide is a very marked and suitable crystallizer.

In order to ada. t the coefiicient of expansion to other coe cients of expansion other substances can be added such as silica, alumina, lime, magnesium oxide on the one side and potash and soda on the other.

The danger of not acquiring a suflicient degree of opaqueness is extremely small on account of the contents of lithiumoxide present.

Claim:

1. The method of enameling a metal article which consists in applyipg a coating of pow- 

